Evaluation of Antioxidant and Antifungal Activity of Chamaecyparis obtuse Extract for Use in Oral Herbal Medicine

The aim of this study was to investigate the antifungal and antioxidant activities of Chamaecyparis obtusa (C. obtusa) extract (COE) against Candida albicans (C. albicans). Methods: The antioxidant activity was determined using three methods based on 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) scavenging, total polyphenol measurement, and total flavonoid measurement. In addition, the survival rate of human keratinocytes (HaCaT) was checked to confirm their stability. A one-way ANOVA also confirmed the antifungal activity of COE against C. albicans and its proliferative effect on HaCaT cells. In addition, to confirm the difference between each group, the Tukey HSD test was performed as a post hoc analysis, and the significance level was set at 0.05 as a two-tailed test. Results: COE was found to contain 424.150 mg GAE/g of polyphenols, 127.566 mg CE/g of flavonoids, and 83.594% of radical scavenging activity. Furthermore, 30 mg/mL of this extract exhibited complete antifungal activity. In addition, a noticeable killing effect on C. albicans was observed as the concentration of the extract increased. For instance, at a 2.5 mg/mL dosage of COE, HaCaT cells were safe, but C. albicans showed a distinct antifungal effect. Conclusions: COE has antioxidant and antifungal activity, so it has a high potential as an effective natural antifungal agent. Therefore, oral gargle containing COE is expected to be a safe and effective treatment in oral candidiasis in clinical practice.